Numerical modelling of the mesofracture process of sintered 316L steel under tension using microtomography

Abstract

This paper concerns numerical modelling of the deformation process, taking into account the local fracture of porous 316L sinters at the mesoscopic scale using the finite element method. Calculations are performed with the use of geometrical models, to map the realistic shape of the porous mesostructure of the material, obtained by means of computed microtomography. The microtomographic device has limited and insufficient measurement accuracy for materials such as the porous sinters studied. For this reason, a method to compensate the inaccuracy of mesostructure shape-mapping is used in the numerical modelling of the deformation and fracture process of the material. The normalised Cockroft-Latham ductile fracture criterion is used to model the local fracture process (at the mesostructure level) of porous metal sinters under tension. The paper describes the numerical modelling procedure and the results of the calculations. The influence of the material structure on the meso-scale fracture process is also discussed. The numerical nominal stress–strain curves are compared with the results of experimental testing. The analysis of stress and strain fields and their variability caused by local fracture in the investigated heterogeneous material is also carried out.